Neutrophils as effectors of vascular inflammation

Lead-induced actin polymerization aggravates neutrophil extracellular trap formation and contributes to vascular inflammation

Lead (Pb) exposure is widely acknowledged as a risk factor for cardiovascular diseases. Previous studies have established neutrophil involvement in Pb-induced cardiovascular injuries; however, the underlying mechanisms remain unclear. To address this knowledge gap, the binding targets of Pb in neutrophils and their roles in regulating neutrophil extracellular trap (NET) formation were investigated. Furthermore, their impact on Pb-induced vascular inflammation and other cardiovascular injuries was studied in mice. Our findings indicate, for the first time, that Pb binds to β-actin in neutrophils, influencing NET formation. Inhibition of actin polymerization reduces the release of extracellular myeloperoxidase, neutrophil elastase, and citrullinated histone H3, indicating an impediment in NET formation. Furthermore, Pb exposure exacerbates blood pressure and vascular inflammation in vascular tissues, leading to abnormal aortic blood flow in mice. These injuries are potentially associated with NET formation, which is supported by the positive correlation between NETs and vascular inflammation. Importantly, the inhibition of actin polymerization mitigates Pb-induced vascular inflammation and regulates systolic blood pressure by reducing NET formation. Collectively, our findings provide novel insights into the mechanism underlying Pb-induced cardiovascular injury, contributing to the management of the escalating risk associated with Pb-induced cardiovascular damage.

Autoimmune diseases and atherosclerotic cardiovascular disease

Autoimmune diseases are associated with a dramatically increased risk of atherosclerotic cardiovascular disease and its clinical manifestations. The increased risk is consistent with the notion that atherogenesis is modulated by both protective and disease-promoting immune mechanisms. Notably, traditional cardiovascular risk factors such as dyslipidaemia and hypertension alone do not explain the increased risk of cardiovascular disease associated with autoimmune diseases. Several mechanisms have been implicated in mediating the autoimmunity-associated cardiovascular risk, either directly or by modulating the effect of other risk factors in a complex interplay. Aberrant leukocyte function and pro-inflammatory cytokines are central to both disease entities, resulting in vascular dysfunction, impaired resolution of inflammation and promotion of chronic inflammation. Similarly, loss of tolerance to self-antigens and the generation of autoantibodies are key features of autoimmunity but are also implicated in the maladaptive inflammatory response during atherosclerotic cardiovascular disease. Therefore, immunomodulatory therapies are potential efficacious interventions to directly reduce the risk of cardiovascular disease, and biomarkers of autoimmune disease activity could be relevant tools to stratify patients with autoimmunity according to their cardiovascular risk. In this Review, we discuss the pathophysiological aspects of the increased cardiovascular risk associated with autoimmunity and highlight the many open questions that need to be answered to develop novel therapies that specifically address this unmet clinical need.

Neutrophils in sickle cell disease: Exploring their potential role as a therapeutic target

Factors influencing the activation of neutrophils in SCD and the potential neutrophil-mediated ameliorating effects of therapies in SCD.

Relationship between pan-immune- inflammation value and in major cardiovascular and cerebrovascular events in stable coronary artery disease patients undergoing on-pump coronary artery bypass graft surgery

BACKGROUND

In this study, we aimed to evaluate the association of pan-immune-inflammation value (PIV) with major cardiovascular and cerebrovascular events (MACCE) in stable coronary artery disease patients undergoing on-pump coronary artery bypass graft (CABG) surgery.

METHODS

We retrospectively analyzed data from 527 patients who underwent on-pump CABG surgery for stable coronary artery disease between June 2015 and December 2020. Patients were categorized into two groups based on MACCE development. PIV levels were calculated from blood samples taken on admission. PIV was calculated as [neutrophil count (×103/µL)×platelet count (×103/µL))×monocyte count (×103/µL)]/lymphocyte count (×103/µL). The primary endpoint was long-term major cardiovascular and cerebrovascular events (MACCE) at a median follow-up of 4.6 years.

RESULTS

Of the included patients, 103 (19.5%) developed MACCE. PIV was higher in patients with MACCE compared to those without (470.8 [295.3-606.8] vs. 269.8 [184.3-386.4], p < 0.001). Multivariate analysis showed a significant positive association between PIV and MACCE (HR: 1.326, 95%CI:1.212-1452, p < 0.001). The cut-off value for the PIV in the estimation of MACCE was 368.28 ( AUC: 0.726 with 69% sensitivity, 71% specificity, p < 0.001).

CONCLUSION

This study shows a significant link between high PIV levels and MACCE in stable coronary artery disease patients undergoing on-pump CABG surgery. Our findings suggest that PIV may be a valuable, routinely available, and inexpensive marker for identifying patients at increased risk of MACCE.

Semaglutide modulates prothrombotic and atherosclerotic mechanisms, associated with epicardial fat, neutrophils and endothelial cells network

BACKGROUND

Obesity has increased in recent years with consequences on diabetes and other comorbidities. Thus, 1 out of 3 diabetic patients suffers cardiovascular disease (CVD). The network among glucose, immune system, endothelium and epicardial fat has an important role on pro-inflammatory and thrombotic mechanisms of atherogenesis. Since semaglutide, long-acting glucagon like peptide 1- receptor agonist (GLP-1-RA), a glucose-lowering drug, reduces body weight, we aimed to study its effects on human epicardial fat (EAT), aortic endothelial cells and neutrophils as atherogenesis involved-cardiovascular cells.

METHODS

EAT and subcutaneous fat (SAT) were collected from patients undergoing cardiac surgery. Differential glucose consumption and protein cargo of fat-released exosomes, after semaglutide or/and insulin treatment were analyzed by enzymatic and TripleTOF, respectively. Human neutrophils phenotype and their adhesion to aortic endothelial cells (HAEC) or angiogenesis were analyzed by flow cytometry and functional fluorescence analysis. Immune cells and plasma protein markers were determined by flow cytometry and Luminex-multiplex on patients before and after 6 months treatment with semaglutide.

RESULTS

GLP-1 receptor was expressed on fat and neutrophils. Differential exosomes-protein cargo was identified on EAT explants after semaglutide treatment. This drug increased secretion of gelsolin, antithrombotic protein, by EAT, modulated CD11b on neutrophils, its migration and endothelial adhesion, induced by adiposity protein, FABP4, or a chemoattractant. Monocytes and neutrophils phenotype and plasma adiposity, stretch, mesothelial, fibrotic, and inflammatory markers on patients underwent semaglutide treatment for 6 months showed a 20% reduction with statistical significance on FABP4 levels and an 80% increase of neutrophils-CD88.

CONCLUSION

Semaglutide increases endocrine activity of epicardial fat with antithrombotic properties. Moreover, this drug modulates the pro-inflammatory and atherogenic profile induced by the adiposity marker, FABP4, which is also reduced in patients after semaglutide treatment.

An Easy-to-Use Nomogram Based on SII and SIRI to Predict in-Hospital Mortality Risk in Elderly Patients with Acute Myocardial Infarction

Aim

Inflammatory response is closely associated with poor prognosis in elderly patients with acute myocardial infarction (AMI). The aim of this study was to develop an easy-to-use predictive model based on medical history data at admission, systemic immune inflammatory index (SII), and systemic inflammatory response index (SIRI) to predict the risk of in-hospital mortality in elderly patients with AMI.

Methods

We enrolled 1550 elderly AMI patients (aged ≥60 years) with complete medical history data and randomized them 5:5 to the training and validation cohorts. Univariate and multivariate logistic regression analyses were used to screen risk factors associated with outcome events (in-hospital death) and to establish a nomogram. The discrimination, calibration, and clinical application value of nomogram were evaluated based on receiver operating characteristic (ROC) curve, calibration curve, and decision curve analysis (DCA), respectively.

Results

The results of multivariate logistic regression showed that age, body mass index (BMI), previous stroke, diabetes, SII, and SIRI were associated with in-hospital death, and these indicators will be included in the final prediction model, which can be obtained by asking the patient's medical history and blood routine examination in the early stage of admission and can improve the utilization rate of the prediction model. The areas under the ROC curve for the training and validation cohorts nomogram were 0.824 (95% CI 0.796 to 0.851) and 0.809 (95% CI 0.780 to 0.836), respectively. Calibration curves and DCA showed that nomogram could better predict the risk of in-hospital mortality in elderly patients with AMI.

Conclusion

The nomogram constructed by combining SII, SIRI, and partial medical history data (age, BMI, previous stroke, and diabetes) at admission has a good predictive effect on the risk of in-hospital death in elderly patients with AMI.

NETworking with cancer: The bidirectional interplay between cancer and neutrophil extracellular traps

Neutrophils are major effectors and regulators of the immune system. They play critical roles not only in the eradication of pathogens but also in cancer initiation and progression. Conversely, the presence of cancer affects neutrophil activity, maturation, and lifespan. By promoting or repressing key neutrophil functions, cancer cells co-opt neutrophil biology to their advantage. This co-opting includes hijacking one of neutrophils' most striking pathogen defense mechanisms: the formation of neutrophil extracellular traps (NETs). NETs are web-like filamentous extracellular structures of DNA, histones, and cytotoxic granule-derived proteins. Here, we discuss the bidirectional interplay by which cancer stimulates NET formation, and NETs in turn support disease progression. We review how vascular dysfunction and thrombosis caused by neutrophils and NETs underlie an elevated risk of death from cardiovascular events in cancer patients. Finally, we propose therapeutic strategies that may be effective in targeting NETs in the clinical setting.

Neutrophils as drivers of vascular injury in sickle cell disease

While neutrophils are the main effectors of protective innate immune responses, they are also key players in inflammatory pathologies. Sickle cell disease (SCD) is a genetic blood disorder in which red blood cells (RBCs) are constantly destroyed in the circulation which generates a highly inflammatory environment that culminates in vascular occlusions. Vaso-occlusion is the hallmark of SCD and a predictor of disease severity. Neutrophils initiate and propagate SCD-related vaso-occlusion through adhesive interactions with the activated and dysfunctional endothelium, sickle RBCs, and platelets, leading to acute and chronic complications that progress to irreversible organ damage and ultimately death. The use of SCD humanized mouse models, in combination with in vivo imaging techniques, has emerged as a fundamental tool to understand the dynamics of neutrophils under complex inflammatory contexts and their contribution to vascular injury in SCD. In this review, we discuss the various mechanisms by which circulating neutrophils sense and respond to the wide range of stimuli present in the blood of SCD patients and mice. We argue that the central role of neutrophils in SCD can be rationalized to develop targets for the management of clinical complications in SCD patients.

Worsening Thrombotic Complication of Atherosclerotic Plaques Due to Neutrophils Extracellular Traps: A Systematic Review

Neutrophil extracellular traps (NETs) recently emerged as a newly recognized contributor to venous and arterial thrombosis. These strands of DNA, extruded by activated or dying neutrophils, decorated with various protein mediators, become solid-state reactors that can localize at the critical interface of blood with the intimal surface of diseased arteries alongside propagating and amplifying the regional injury. NETs thus furnish a previously unsuspected link between inflammation, innate immunity, thrombosis, oxidative stress, and cardiovascular diseases. In response to disease-relevant stimuli, neutrophils undergo a specialized series of reactions that culminate in NET formation. DNA derived from either nuclei or mitochondria can contribute to NET formation. The DNA liberated from neutrophils forms a reticular mesh that resembles morphologically a net, rendering the acronym NETs particularly appropriate. The DNA backbone of NETs not only presents intrinsic neutrophil proteins (e.g., MPO (myeloperoxidase) and various proteinases) but can congregate other proteins found in blood (e.g., tissue factor procoagulant). This systematic review discusses the current hypothesis of neutrophil biology, focusing on the triggers and mechanisms of NET formation. Furthermore, the contribution of NETs to atherosclerosis and thrombosis is extensively addressed. Again, the use of NET markers in clinical trials was considered. Ultimately, given the vast body of the published literature, we aim to integrate the experimental evidence with the growing body of clinical information relating to NET critically.

Neutrophil profiles of pediatric COVID-19 and multisystem inflammatory syndrome in children

Multisystem inflammatory syndrome in children (MIS-C) is a delayed-onset, COVID-19-related hyperinflammatory illness characterized by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) antigenemia, cytokine storm, and immune dysregulation. In severe COVID-19, neutrophil activation is central to hyperinflammatory complications, yet the role of neutrophils in MIS-C is undefined. Here, we collect blood from 152 children: 31 cases of MIS-C, 43 cases of acute pediatric COVID-19, and 78 pediatric controls. We find that MIS-C neutrophils display a granulocytic myeloid-derived suppressor cell (G-MDSC) signature with highly altered metabolism that is distinct from the neutrophil interferon-stimulated gene (ISG) response we observe in pediatric COVID-19. Moreover, we observe extensive spontaneous neutrophil extracellular trap (NET) formation in MIS-C, and we identify neutrophil activation and degranulation signatures. Mechanistically, we determine that SARS-CoV-2 immune complexes are sufficient to trigger NETosis. Our findings suggest that hyperinflammatory presentation during MIS-C could be mechanistically linked to persistent SARS-CoV-2 antigenemia, driven by uncontrolled neutrophil activation and NET release in the vasculature.

Expression profiles and functions of ferroptosis-related genes in the placental tissue samples of early- and late-onset preeclampsia patients

Background

The accumulation of reactive oxygen species (ROS) resulting from upregulated levels of oxidative stress is commonly implicated in preeclampsia (PE). Ferroptosis is a novel form of iron-dependent cell death instigated by lipid peroxidation that likely plays an important role in PE pathogenesis. This study aimed to investigate the expression profiles and functions of ferroptosis-related genes (FRGs) in early-onset preeclampsia (EOPE) and late-onset preeclampsia (LOPE).

Methods

Gene expression data and clinical information were downloaded from the Gene Expression Omnibus (GEO) database. The “limma” R package was used to screen differentially expressed genes. Gene Ontology (GO), Kyoto Encyclopedia of Genes and Genomes (KEGG) and protein–protein interaction (PPI) network analyses were conducted to investigate the bioinformatics functions and molecular interactions of significantly different FRGs. Quantitative reverse transcription polymerase chain reaction (RT-qPCR) was used to verify the expression of hub FRGs in PE.

Results

A total of 4215 differentially expressed genes (DEGs) were identified between EOPE and preterm cases while 556 DEGs were found between LOPE and term controls. Twenty significantly different FRGs were identified in EOPE subtypes, while only 3 FRGs were identified in LOPE subtypes. Functional enrichment analysis revealed that the differentially expressed FRGs were mainly involved in EOPE and enriched in hypoxia- and iron-related pathways, such as the response to hypoxia, iron homeostasis and iron ion binding process. PPI network analysis and verification by RT-qPCR resulted in the identification of the following five FRGs of interest: FTH1, HIF1A, FTL, MAPK8 and PLIN2.

Conclusions

EOPE and LOPE have distinct underlying molecular mechanisms, and ferroptosis may be mainly implicated in the pathogenesis of EOPE. Further studies are necessary for deeper inquiry into placental ferroptosis and its role in the pathogenesis of EOPE.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12884-022-04423-6.

Neutrophil DREAM promotes neutrophil recruitment in vascular inflammation

The interaction between neutrophils and endothelial cells is critical for the pathogenesis of vascular inflammation. However, the regulation of neutrophil adhesive function remains not fully understood. Intravital microscopy demonstrates that neutrophil DREAM promotes neutrophil recruitment to sites of inflammation induced by TNF-α but not MIP-2 or fMLP. We observe that neutrophil DREAM represses expression of A20, a negative regulator of NF-κB activity, and enhances expression of pro-inflammatory molecules and phosphorylation of IκB kinase (IKK) after TNF-α stimulation. Studies using genetic and pharmacologic approaches reveal that DREAM deficiency and IKKβ inhibition significantly diminish the ligand-binding activity of β2 integrins in TNF-α-stimulated neutrophils or neutrophil-like HL-60 cells. Neutrophil DREAM promotes degranulation through IKKβ-mediated SNAP-23 phosphorylation. Using sickle cell disease mice lacking DREAM, we show that hematopoietic DREAM promotes vaso-occlusive events in microvessels following TNF-α challenge. Our study provides evidence that targeting DREAM might be a novel therapeutic strategy to reduce excessive neutrophil recruitment in inflammatory diseases.

In Vivo Imaging of Circadian NET Formation During Lung Injury by Four-Dimensional Intravital Microscopy

Neutrophil extracellular traps (NETs) are toxic extracellular structures deployed by neutrophils in response to pathogens and sterile danger signals. NETs are circadian in nature as mouse and human neutrophils preferentially deploy them at night or early morning. Traditionally, NETs have been quantified using a plethora of methods including immunofluorescence and ELISA-based assays; however few options are available to visualize them in vivo. Here we describe a method to directly visualize and quantify NET formation and release in the microvasculature of the lung using intravital imaging in a model of acute lung injury. The method allows four-dimensional capture and quantification of NET formation dynamics over time and should be a useful resource for those interested in visualizing neutrophil responses in vivo.

The Prognostic Significance of Neutrophil to Lymphocyte Ratio (NLR), Monocyte to Lymphocyte Ratio (MLR) and Platelet to Lymphocyte Ratio (PLR) on Long-Term Survival in Off-Pump Coronary Artery Bypass Grafting (OPCAB) Procedures

BACKGROUND

Cardiovascular diseases, apart from commonly known risk factors, are related to inflammation. There are several simple novel markers proposed to present the relation between inflammatory reactions activation and atherosclerotic changes. They are easily available from whole blood count and include neutrophil to lymphocyte ratio (NLR), monocyte to lymphocyte ratio (MLR), and platelets to lymphocyte ratio (PLR). The RDW results were excluded from the analysis.

METHOD AND RESULTS

The study based on retrospective single-centre analysis of 682 consecutive patients (131 (19%) females and 551 (81%) males) with median age of 66 years (60-71) who underwent off-pump coronary artery bypass grafting (OPCAB) procedure. During the median 5.3 +/- 1.9 years follow-up, there was a 87% cumulative survival rate. The laboratory parameters including preoperative MLR > 0.2 (HR 2.46, 95% CI 1.33-4.55, p = 0.004) and postoperative NLR > 3.5 (HR 1.75, 95% CI 1.09-2.79, p = 0.019) were found significant for long-term mortality prediction in multivariable analysis.

CONCLUSION

Hematological indices NLR and MLR can be regarded as significant predictors of all-cause long-term mortality after OPCAB revascularization. Multivariable analysis revealed preoperative values of MLR > 0.2 and postoperative values of NLR > 3.5 as simple, reliable factors which may be applied into clinical practice for meticulous postoperative monitoring of patients in higher risk of worse prognosis.

Zinc-dependent histone deacetylases drive neutrophil extracellular trap formation and potentiate local and systemic inflammation

Neutrophil extracellular traps (NETs) have been implicated in the pathogenesis of acute respiratory distress syndrome (ARDS) driven by viruses or bacteria, as well as in numerous immune-mediated disorders. Histone citrullination by the enzyme peptidylarginine deiminase 4 (PAD4) and the consequent decondensation of chromatin are hallmarks in the induction of NETs. Nevertheless, additional histone modifications that may govern NETosis are largely overlooked. Herein, we show that histone deacetylases (HDACs) play critical roles in driving NET formation in human and mouse neutrophils. HDACs belonging to the zinc-dependent lysine deacetylases family are necessary to deacetylate histone H3, thus allowing the activity of PAD4 and NETosis. Of note, HDAC inhibition in mice protects against microbial-induced pneumonia and septic shock, decreasing NETosis and inflammation. Collectively, our findings illustrate a new fundamental step that governs the release of NETs and points to HDAC inhibitors as therapeutic agents that may be used to protect against ARDS and sepsis.

Pulmonary vascular system: A vulnerable target for COVID-19

The number of coronavirus disease 2019 (COVID‐19) cases has been increasing significantly, and the disease has evolved into a global pandemic, posing an unprecedented challenge to the healthcare community. Angiotensin‐converting enzyme 2, the binding and entry receptor of severe acute respiratory syndrome coronavirus 2 (SARS‐CoV‐2) in hosts, is also expressed on pulmonary vascular endothelium; thus, pulmonary vasculature is a potential target in COVID‐19. Indeed, pulmonary vascular thickening is observed by early clinical imaging, implying a tropism of SARS‐CoV‐2 for pulmonary vasculature. Recent studies reported that COVID‐19 is associated with vascular endothelial damage and dysfunction along with inflammation, coagulopathy, and microthrombosis; all of these pathologic changes are the hallmarks of pulmonary vascular diseases. Notwithstanding the not fully elucidated effects of COVID‐19 on pulmonary vasculature, the vascular endotheliopathy that occurs after infection is attributed to direct infection and indirect damage mainly caused by renin‐angiotensin‐aldosterone system imbalance, coagulation cascade, oxidative stress, immune dysregulation, and intussusceptive angiogenesis. Degradation of endothelial glycocalyx exposes endothelial cell (EC) surface receptors to the vascular lumen, which renders pulmonary ECs more susceptible to SARS‐CoV‐2 infection. The present article reviews the potential pulmonary vascular pathophysiology and clinical presentations in COVID‐19 to provide a basis for clinicians and scientists, providing insights into the development of therapeutic strategies targeting pulmonary vasculature.

Neutrophil Extracellular Traps (NETs) in Cancer Invasion, Evasion and Metastasis

Simple Summary

This review focuses on the pro-tumorigenic action of neutrophil extracellular traps (NETs). NETs were found in various samples of human and animal tumors. The role of the NETs in tumor development increasingly includes cancer immunoediting and interactions between immune system and cancer cells. NETs awake dormant cancer cells, play a key regulatory role in the tumor microenvironment, and exacerbate tumor aggressiveness by enhancing cancer migration and invasion capacity. Furthermore, NETs induce the epithelial to mesenchymal transition in tumor cells. NET proteinases can also degrade the extracellular matrix, promoting cancer cell extravasation. Moreover, NETs can entrap circulating cancer cells and, in that way, facilitate metastasis. A better understanding of the crosstalk between cancer and NETs can help to devise novel approaches to the therapeutic interventions that block cancer evasion mechanisms and prevent metastatic spread.

Abstract

The present review highlights the complex interactions between cancer and neutrophil extracellular traps (NETs). Neutrophils constitute the first line of defense against foreign invaders using major effector mechanisms: phagocytosis, degranulation, and NETs formation. NETs are composed from decondensed nuclear or mitochondrial DNA decorated with proteases and various inflammatory mediators. Although NETs play a crucial role in defense against systemic infections, they also participate in non-infectious conditions, such as inflammation, autoimmune disorders, and cancer. Cancer cells recruit neutrophils (tumor-associated neutrophils, TANs), releasing NETs to the tumor microenvironment. NETs were found in various samples of human and animal tumors, such as pancreatic, breast, liver, and gastric cancers and around metastatic tumors. The role of the NETs in tumor development increasingly includes cancer immunoediting and interactions between the immune system and cancer cells. According to the accumulated evidence, NETs awake dormant cancer cells, causing tumor relapse, as well as its unconstrained growth and spread. NETs play a key regulatory role in the tumor microenvironment, such as the development of distant metastases through the secretion of proteases, i.e., matrix metalloproteinases and proinflammatory cytokines. NETs, furthermore, directly exacerbate tumor aggressiveness by enhancing cancer migration and invasion capacity. The collected evidence also states that through the induction of the high-mobility group box 1, NETs induce the epithelial to mesenchymal transition in tumor cells and, thereby, potentiate their invasiveness. NET proteinases can also degrade the extracellular matrix, promoting cancer cell extravasation. Moreover, NETs can entrap circulating cancer cells and, in that way, facilitate metastasis. NETs directly trigger tumor cell proliferation through their proteases or activating signals. This review focused on the pro-tumorigenic action of NETs, in spite of its potential to also exhibit an antitumor effect. NET components, such as myeloperoxidase or histones, have been shown to directly kill cancer cells. A better understanding of the crosstalk between cancer and NETs can help to devise novel approaches to the therapeutic interventions that block cancer evasion mechanisms and prevent metastatic spread. This review sought to provide the most recent knowledge on the crosstalk between NETs and cancer, and bring more profound ideas for future scientists exploring this field.

The misunderstood link between SARS-CoV-2 and angiogenesis. A narrative review

Novel Coronavirus Disease 2019 (Covid-19) is associated with multi-systemic derangement, including circulatory dysfunction with features of endothelial dysfunction, microangiopathic thrombosis and angiocentric inflammation. Recently, intussusceptive angiogenesis has been implicated in the pathogenesis of the disease. Herein, we conducted a narrative review according to the SANRA guidelines to review and discuss data regarding splitting angiogenesis including mechanisms, drivers, regulators and putative roles. Relevant angiogenic features in Covid-19, including their potential role in inflammation, endothelial dysfunction and permeability, as well as their use as prognostic markers and therapeutic roles are reviewed. Splitting angiogenesis in Covid-19 involve hypoxia, hypoxia-inducible factors, classic angiogenic mediators, such as the Vascular Endothelial Growth Factor (VEGF), Angiopoietins, hyperinflammation and cytokine storm, and dysregulation of the Renin-Angiotensin-Aldosterone System, which combined, interact to promote intussusception. Data regarding the use of angiogenic mediators as prognostic tools is summarized and suggest that angiopoietins and VEGF are elevated in Covid-19 patients and predictors of adverse outcomes. Finally, we reviewed the scarce data regarding angiogenic mediators as therapeutic targets. These preliminary findings suggest a potential benefit of bevacizumab as an add-on therapy.

Targeting Cytokines, Pathogen-Associated Molecular Patterns, and Damage-Associated Molecular Patterns in Sepsis via Blood Purification

Sepsis is characterized by a dysregulated immune response to infections that causes life-threatening organ dysfunction and even death. When infections occur, bacterial cell wall components (endotoxin or lipopolysaccharide), known as pathogen-associated molecular patterns, bind to pattern recognition receptors, such as toll-like receptors, to initiate an inflammatory response for pathogen elimination. However, strong activation of the immune system leads to cellular dysfunction and ultimately organ failure. Damage-associated molecular patterns (DAMPs), which are released by injured host cells, are well-recognized triggers that result in the elevation of inflammatory cytokine levels. A cytokine storm is thus amplified and sustained in this vicious cycle. Interestingly, during sepsis, neutrophils transition from powerful antimicrobial protectors into dangerous mediators of tissue injury and organ dysfunction. Thus, the concept of blood purification has evolved to include inflammatory cells and mediators. In this review, we summarize recent advances in knowledge regarding the role of lipopolysaccharides, cytokines, DAMPs, and neutrophils in the pathogenesis of sepsis. Additionally, we discuss the potential of blood purification, especially the adsorption technology, for removing immune cells and molecular mediators, thereby serving as a therapeutic strategy against sepsis. Finally, we describe the concept of our immune-modulating blood purification system.

Carbon Monoxide-Releasing Molecule-2 Ameliorates Particulate Matter-Induced Aorta Inflammation via Toll-Like Receptor/NADPH Oxidase/ROS/NF-κB/IL-6 Inhibition

Particulate matter (PM), a major air pollutant, may be associated with adverse cardiovascular effects. Reactive oxygen species- (ROS-) dependent proinflammatory cytokine production, such as interleukin-6 (IL-6), is a possible underlying mechanism. Carbon monoxide- (CO-) releasing molecule-2 (CORM-2) which liberates exogenous CO can exert many beneficial effects, particularly anti-inflammation and antioxidant effects. The purpose of this study was to explore the protective effects and underpinning mechanisms of CORM-2 on PM-induced aorta inflammation. Here, human aortic vascular smooth muscle cells (HASMCs) were utilized as in vitro models for the assessment of signaling pathways behind CORM-2 activities against PM-induced inflammatory responses, including Toll-like receptors (TLRs), NADPH oxidase, ROS, nuclear factor-kappa B (NF-κB), and IL-6. The modulation of monocyte adherence and HASMC migration, that are two critical cellular events of inflammatory process, along with their regulators, including intercellular adhesion molecule-1 (ICAM-1), vascular cell adhesion molecule-1 (VCAM-1), and matrix metalloproteinase-2 (MMP-2) and MMP-9, in response to PM by CORM-2, were further evaluated. Finally, mice experiments under different conditions were conducted for the in vivo evaluation of CORM-2 benefits on the expression of inflammatory molecules including IL-6, ICAM-1, VCAM-1, MMP-2, and MMP-9. Our results found that PM could induce aorta inflammation in vitro and in vivo, as evidenced by the increase of IL-6 expression that was regulated by the TLR2 and TLR4/NADPH oxidase/ROS/NF-κB signaling pathway, thereby promoting ICAM-1- and VCAM-1-dependent monocyte adhesion and MMP-2- and MMP-9-dependent HASMC migration. Importantly, our experimental models demonstrated that CORM-2-liberated CO effectively inhibited the whole identified PM-induced inflammatory cascade in HASMCs and tissues. In conclusion, CORM-2 treatment may elicit multiple beneficial effects on inflammatory responses of aorta due to PM exposure, thereby providing therapeutic value in the context of inflammatory diseases of the cardiovascular system.

Panoramic imaged carotid atheromas are associated with increased neutrophil count: both validated, independent predictors of near-term myocardial infarction

OBJECTIVES

Panoramic images (PXs) demonstrating calcified carotid artery atheromas (CCAAs) are associated with heightened risk of near-term myocardial infarction (MI). Elevated neutrophil counts (NC) within normal range 2,500-6,000 per mm³ are likewise associated with future MI signaling the role neutrophils play in the chronic inflammation process underlying coronary artery atherogenesis. We determined if CCAAs on PXs are associated with increased NC.

METHODS

Investigators implemented a retrospective study of PXs and accompanying medical records of white males ≥ 65 years treated by a VA dental service. Two groups (N = 60 each) were constituted, one with atheromas (CCAA+) and one without (CCAA-). Predictor variable was CCAA + and outcome variable was NC. Bootstrapping analysis determined the difference in mean NCs between two groups, significance set at ≤0.05.

RESULTS

The study group of (CCAA+) (mean age 75.9; range 69-91 years) demonstrated a mean NC of 4,843 per mm³ and control group (CCAA-) (mean age 75.3; range; 66-94) a mean NC of 4,108 per mm³. The difference between the groups was significant (p = 0.0008) (95% CI of difference of mean: -432, 431; observed effect size 736).

CONCLUSIONS

CCAAs on PXs of elderly white males are associated with elevated NC; amplifying need for medical consultation prior to invasive dental procedures.

Neutrophil to Lymphocyte Ratio Is Increased and Associated With Left Ventricular Diastolic Function in Newly Diagnosed Essential Hypertension Children

Aim: Hypertension is associated with cardiac structural and functional changes, including left ventricular hypertrophy (LVH) and LV systolic dysfunction diastolic dysfunction. Neutrophil-to-lymphocyte ratio (NLR) is a novel inflammatory biomarker associated with cardiovascular diseases. The current study aimed to evaluate NLR in children with newly diagnosed essential hypertension and its relationship between blood pressure and cardiac changes. Methods and Subjects: Sixty-five children with newly diagnosed essential hypertension and 54 healthy children were included. Clinical characteristics, blood cell counts, and biochemical parameters were collected. LVH was assessed by calculation of LV mass index (LVMI), and LV systolic function was evaluated by measuring LV ejection fraction and fractional shortening. LV diastolic function was primarily assessed with E/E' ratio by Doppler and echocardiography. Results: The hypertension children had significantly higher LVMI and E/E' ratio than the controls, whereas there was no difference in LV systolic function between the two groups. The NLR was significantly higher in the hypertension group than the control group. Moreover, NLR was positively correlated with systolic blood pressure (SBP) and diastolic blood pressure (DBP) levels in the hypertension group. Additionally, a significantly positive correlation between NLR and E/E' ratio was found in the hypertension group. However, NLR was not related to LVH and LV systolic function indicators in hypertension children. Conclusion: NLR is elevated in hypertension children, and it is associated positively with office blood pressure levels. Moreover, NLR may help assess LV diastolic function in hypertension children.

Curcumin as a Potential Treatment for COVID-19

Coronavirus disease 2019 (COVID-19) is an infectious disease that rapidly spread throughout the world leading to high mortality rates. Despite the knowledge of previous diseases caused by viruses of the same family, such as MERS and SARS-CoV, management and treatment of patients with COVID-19 is a challenge. One of the best strategies around the world to help combat the COVID-19 has been directed to drug repositioning; however, these drugs are not specific to this new virus. Additionally, the pathophysiology of COVID-19 is highly heterogeneous, and the way of SARS-CoV-2 modulates the different systems in the host remains unidentified, despite recent discoveries. This complex and multifactorial response requires a comprehensive therapeutic approach, enabling the integration and refinement of therapeutic responses of a given single compound that has several action potentials. In this context, natural compounds, such as Curcumin, have shown beneficial effects on the progression of inflammatory diseases due to its numerous action mechanisms: antiviral, anti-inflammatory, anticoagulant, antiplatelet, and cytoprotective. These and many other effects of curcumin make it a promising target in the adjuvant treatment of COVID-19. Hence, the purpose of this review is to specifically point out how curcumin could interfere at different times/points during the infection caused by SARS-CoV-2, providing a substantial contribution of curcumin as a new adjuvant therapy for the treatment of COVID-19.

Elongated neutrophil-derived structures are blood-borne microparticles formed by rolling neutrophils during sepsis

Rolling neutrophils form tethers with submicron diameters. Here, we report that these tethers detach, forming elongated neutrophil-derived structures (ENDS) in the vessel lumen. We studied ENDS formation in mice and humans in vitro and in vivo. ENDS do not contain mitochondria, endoplasmic reticulum, or DNA, but are enriched for S100A8, S100A9, and 57 other proteins. Within hours of formation, ENDS round up, and some of them begin to present phosphatidylserine on their surface (detected by annexin-5 binding) and release S100A8-S100A9 complex, a damage-associated molecular pattern protein that is a known biomarker of neutrophilic inflammation. ENDS appear in blood plasma of mice upon induction of septic shock. Compared with healthy donors, ENDS are 10-100-fold elevated in blood plasma of septic patients. Unlike neutrophil-derived extracellular vesicles, most ENDS are negative for the tetraspanins CD9, CD63, and CD81. We conclude that ENDS are a new class of bloodborne submicron particles with a formation mechanism linked to neutrophil rolling on the vessel wall.

Prognostic value of inflammatory biomarkers and GRACE score for cardiac death and acute kidney injury after acute coronary syndromes

AIMS 

The aim of this study was to analyse the role of inflammation and established clinical scores in predicting acute kidney injury (AKI) after acute coronary syndromes (ACS).

METHODS AND RESULTS 

In a prospective multicentre cohort including 2034 patients with ACS undergoing percutaneous coronary intervention, high-sensitivity C-reactive protein (hsCRP), neutrophil count, neutrophil-to-lymphocyte ratio (NL-ratio), and creatinine were measured at the index procedure. AKI (n = 39, defined according to RIFLE criteria) and major cardiovascular and cerebrovascular events were adjudicated after 1 year. Associations between inflammation, AKI, and cardiac death (CD) were assessed by C-statistics and Cox proportional hazard models with log-rank test to compare survival. Patients with ACS with elevated neutrophil count >7.8 × 109/L, NL-ratio >5, combined neutrophil-count/creatinine, or NL-ratio/creatinine at baseline showed a higher incidence of AKI (all P < 0.05) and CD (all P < 0.001). The risk of AKI, CD, and their combination was increased in patients with higher neutrophil count/creatinine (heart rate (HR) = 3.7, 95% cardiac index (CI) 1.9-7.1; HR = 2.7, 95% CI 1.6-4.6; HR = 3.2, 95% CI 2.1-4.9); NL-ratio/creatinine (HR = 2.1, 95% CI 1.6-4.1; HR = 2.2, 95% CI 1.3-3.8; HR = 2.3, 95% CI 1.5-3.5); and hsCRP (HR = 1.8, 95% CI 0.9-3.5; HR = 2.2, 95% CI 1.3-3.6; HR = 1.9, 95% CI 1.2-2.8) after adjustment for age, diabetes, hypertension, previous heart failure, kidney function, haemodynamic instability at admission, statin, and renin-angiotensin-aldosterone antagonists use. Subjects with higher GRACE score 1.0/NL-ratio had higher rate of AKI, CD, and both (HR = 1.4, 95% CI 0.5-4.2; HR = 2.7, 95% CI 1.3-5.9; HR = 2.1, 95% CI 1-4.3).

CONCLUSIONS 

Inflammation markers may predict AKI after correction for renal function at the index procedure. hsCRP performed better than the NL-ratio. However, the integration of inflammation markers to traditional risk factors or scores does not add prognostic information.

TRIAL REGISTRATION 

ClinicalTrials.gov, NCT01000701.

COVID-19 - A vascular disease

Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) leads to multi-system dysfunction with emerging evidence suggesting that SARS-CoV-2-mediated endothelial injury is an important effector of the virus. Potential therapies that address vascular system dysfunction and its sequelae may have an important role in treating SARS-CoV-2 infection and its long-lasting effects.

Redox Signaling and Regional Heterogeneity of Endothelial Dysfunction in db/db Mice

The variable nature of vascular dysfunction in diabetes is not well understood. We explored the functional adaptation of different arteries in db/db mice in relation to increased severity and duration of diabetes. We compared endothelium-dependent and -independent vasodilation in the aortae, as well as the carotid and femoral arteries, of db/db mice at three ages in parallel with increased body weight, oxidative stress, and deterioration of glycemic control. Vascular responses to in vitro generation of reactive oxygen species (ROS) and expression of superoxide dismutase (SOD) isoforms were assessed. There was a progressive impairment of endothelium-dependent and -independent vasorelaxation in the aortae of db/db mice. The carotid artery was resistant to the effects of in vivo and in vitro induced oxidative stress, and it maintained unaltered vasodilatory responses, likely because the carotid artery relaxed in response to ROS. The femoral artery was more reliant on dilation mediated by endothelium-dependent hyperpolarizing factor(s), which was reduced in db/db mice at the earliest age examined and did not deteriorate with age. Substantial heterogeneity exists between the three arteries in signaling pathways and protein expression of SODs under physiological and diabetic conditions. A better understanding of vascular heterogeneity will help develop novel therapeutic approaches for targeted vascular treatments, including blood vessel replacement.

Tricuspid regurgitation velocity and other biomarkers of mortality in children, adolescents and young adults with sickle cell disease in the United States: The PUSH study

In the US, mortality in sickle cell disease (SCD) increases after age 18-20 years. Biomarkers of mortality risk can identify patients who need intensive follow-up and early or novel interventions. We prospectively enrolled 510 SCD patients aged 3-20 years into an observational study in 2006-2010 and followed 497 patients for a median of 88 months (range 1-105). We hypothesized that elevated pulmonary artery systolic pressure as reflected in tricuspid regurgitation velocity (TRV) would be associated with mortality. Estimated survival to 18 years was 99% and to 25 years, 94%. Causes of death were known in seven of 10 patients: stroke in four (hemorrhagic two, infarctive one, unspecified one), multiorgan failure one, parvovirus B19 infection one, sudden death one. Baseline TRV ≥2.7 m/second (>2 SD above the mean in age-matched and gender-matched non-SCD controls) was observed in 20.0% of patients who died vs 4.6% of those who survived (P = .012 by the log rank test for equality of survival). The baseline variable most strongly associated with an elevated TRV was a high hemolytic rate. Additional biomarkers associated with mortality were ferritin ≥2000 μg/L (observed in 60% of patients who died vs 7.8% of survivors, P < .001), forced expiratory volume in 1 minute to forced vital capacity ratio (FEV1/FVC) <0.80 (71.4% of patients who died vs 18.8% of survivors, P < .001), and neutrophil count ≥10x10⁹ /L (30.0% of patients who died vs 7.9% of survivors, P = .018). In SCD children, adolescents and young adults, steady-state elevations of TRV, ferritin and neutrophils and a low FEV1/FVC ratio may be biomarkers associated with increased risk of death.

Anti-inflammatory effects of non-statin low-density lipoprotein cholesterol-lowering drugs: an unused potential?

Objectives. Inflammatory responses are closely knit with low-density lipoprotein (LDL)-cholesterol in driving atherosclerosis. Even if LDL-cholesterol is causative to atherosclerotic diseases and LDL-cholesterol lowering reduces hard clinical endpoints, there is a residual risk for clinical events, possibly driven by inflammatory processes, in accordance with its role in autoimmune diseases. Design. As LDL-cholesterol treatment targets are reduced, the use of non-statin lipid-lowering drugs will probably increase. Atherosclerotic plaques evolve through lipid infiltration and modification in the intima, furthermore infiltration of cells including monocytes, macrophages, T-lymphocytes and neutrophils initiating inflammatory signaling. Here we briefly review inflammation in atherosclerosis and the effects of the non-statin lipid-lowering drugs on inflammation. The review is limited to the most common non-statin lipid lowering drugs, i.e. proprotein convertase subtilisin-kexin type 9 (PCSK9) inhibitors, bile acid sequestrants (BAS) and cholesterol absorption inhibitors. Results. PCSK9 inhibition is mostly studied together with statins and is associated with a reduction of pro-inflammatory cytokines. Furthermore, PCSK9 inhibitors seem to have an effect on monocyte migration trough CCR2. They also have an interaction with sirtuins, possibly offering a therapeutic target. BAS have several interesting effects on inflammation, including reduction of pro-inflammatory cytokines and a reduction of the number of infiltrating macrophages, however there are relatively few reports considering that these drugs have been on the market for decades. Ezetimibe also has effects on inflammation including reduction of pro-inflammatory cytokines and adhesion molecules, however these effects are usually accomplished in tandem with statins. Conclusion. This topic adds an interesting piece to the puzzle of atherosclerosis, indicating that PCSK9 inhibition, BAS and ezetimibe all affect thromboinflammation.

Circadian Features of Neutrophil Biology

Rhythms in immunity manifest in multiple ways, but perhaps most prominently by the recurrent onset of inflammation at specific times of day. These patterns are of importance to understand human disease and are caused, in many instances, by the action of neutrophils, a myeloid leukocyte with striking circadian features. The neutrophil's short life, marked diurnal variations in number, and changes in phenotype while in the circulation, help explain the temporal features of inflammatory disease but also uncover core features of neutrophil physiology. Here, we summarize well-established concepts and introduce recent discoveries in the biology of these cells as they relate to circadian rhythms. We highlight that although the circadian features of neutrophils are better known and relevant to understand disease, they may also influence important aspects of organ function even in the steady-state. Finally, we discuss the possibility of targeting these temporal features of neutrophils for therapeutic benefit.

Increased plasmatic NETs by-products in patients in severe obesity

Neutrophil extracellular traps (NETs) are DNAs products involved in immune process. Obesity through a low-grade chronic inflammation determines neutrophil activation, but it is still unclear its role in NETs formation. Here we analyzed the NETs levels in healthy and morbid obese, their association with anthropometric and glyco-metabolic parameters and their changes after bariatric surgery. For this study, we enrolled 73 patients with morbid obesity (BMI ≥40 kg/m² or ≥35 kg/m² + comorbidity) eligible to sleeve gastrectomy. In parallel, 55 healthy subjects and 21 patients with severe coronary artery disease were studied as controls. We evaluated anthropometric parameters, peripheral blood pressure, biochemical and serum analysis at the enrollment and at twelve months after surgery. Plasmatic levels of MPO-DNA complexes were assessed by ELISA. NETs levels were higher in obese than in control group (p < 0.001) and correlated with the main anthropometric variable (BMI, waist, hip), glyco-metabolic variables and systolic blood pressure. NETs trend after intervention was uneven. The reduction of NETs correlated with the entity of reduction of BMI (ρ = 0.416, p < 0.05), visceral fat area (ρ = 0.351, p < 0.05), and glycemia (ρ = 0.495, p < 0.001). In medical history of patients in whom NETs increased, we observed a higher number of thromboembolic events. Our observations indicate that severe obesity is associated with increased generation of NETs, which in turn could influence the patients' systemic inflammatory state. Weight loss and in particular, loss of adipose tissue after bariatric surgery does not in itself correct NET's dysregulated production. Finally, patients in whom NETs accumulation persists after surgery are probably those at the highest risk of cardiovascular events.

Myeloid cells as therapeutic targets in neuroinflammation after stroke: Specific roles of neutrophils and neutrophil-platelet interactions

Ischemic brain injury causes a local inflammatory response, involving the activation of resident brain cells such as microglia and the recruitment of infiltrating immune cells. Increasing evidence supports that plasticity of the myeloid cell lineage is determinant for the specific role of these cells on stroke outcome, from initiation and maintenance to resolution of post-ischemic inflammation. The aim of this review is to summarize some of the key characteristics of these cells and the mechanisms for their recruitment into the injured brain through interactions with platelets, endothelial cells and other leukocytes. Also, we discuss the existence of different leukocyte subsets in the ischemic tissue and, specifically, the impact of different myeloid phenotypes on stroke outcome, with special emphasis on neutrophils and their interplay with platelets. Knowledge of these cellular phenotypes and interactions may pave the way to new therapies able to promote protective immune responses and tissue repair after cerebral ischemia.

Vasculitis Pathogenesis: Can We Talk About Precision Medicine?

Precision medicine is designing the medical care by taking into account the individual variability for each person. We have tried to address whether the existing data may guide precision medicine in primary systemic vasculitides (PSV). We have reviewed genome-wide association studies (GWAS) data, lessons from monogenic mimics of these diseases, and biomarker studies in immunoglobulin A vasculitis/Henoch–Schönlein purpura, Kawasaki disease, anti-neutrophil cytoplasmic antibody-associated vasculitis, polyarteritis nodosa (PAN), Takayasu arteritis, and Behçet’s disease (BD). GWAS provide insights about the pathogenesis of PSV while whole exome sequencing studies lead to discovery of monogenic vasculitides, phenotype of which could mimic other types of vasculitis such as PAN and BD. Monogenic vasculitides form a subgroup of vasculitis which are caused by single gene alterations and discovery of these diseases has enabled more specific therapies in these patients. With increasing number of studies on biomarkers, new targets for treatment appear and better and structured follow-up of PSV patients will become possible. Proteomics and metabolomics studies are required to better categorize our patients with PSV so that we can manage them appropriately and offer more targeted therapy.